1. Field of the Invention
Apparatuses and methods consistent with the present invention relate to creating and applying a secure file identifier (SFID) of a rights object by using random numbers, and more particularly, to efficiently managing and protecting the rights object by disabling the rights object using the SFID when the rights object is transferred and used between a host device and secure removable media (SRM).
2. Description of the Related Art
Recently, when a rights object is transferred and used between a host device and an SRM, a rights object identifier (ROID), as a specific file identifier (FID) for the rights object, is generally hashed into a specific length when the rights object is issued by a rights issuer.
With respect to digital rights management (DRM), the ROID is generally known to be unique. However, there is no known related art method which can fully guarantee the uniqueness of ROIDs.
Generally, in terms of managing efficiency, when creating an FID in a predetermined length to correspond to a rights object stored in an SRM, a hash value of 20 bytes from the ROID is used. However, since the length of the ROIDs may vary according to the rights issuer, the uniqueness of FIDs may be lowered to cause collisions with each other.
Further, although there is a related art method of creating an FID by a separate rule to avoid collision with the existing FIDs and by considering the file management system of SRM, it is difficult to ascertain the relationship to the ROID of a rights object. Thus, there is a need for means to form a relationship between the ROID and the FID.